JP6480535B2 - Piston having oil-cooled passage and method for constructing the same - Google Patents

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of US Provisional Application Serial No. 61 / 674,120, filed July 20, 2012, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates generally to internal combustion engines, and more particularly to pistons and methods for their construction.

2. Related Technologies Engine manufacturers include, but are not limited to: improved fuel economy, improved fuel combustion, reduced oil consumption, increased exhaust temperature for subsequent use of heat in the vehicle, compression load in the cylinder bore Is faced with increasing demands to improve engine efficiency and performance, including increased production, weight reduction, and engine miniaturization. It is therefore desirable to increase the temperature and compression load in the engine combustion chamber. However, increasing the temperature in the combustion chamber and the compression load increases the wear and physical demands on the piston, especially when the operating temperature of the piston exceeds 240-270 ° C., thereby increasing its potential useful life. Shrink. A particular area where temperature rise is a concern is along the upper combustion surface of the piston and within the internal area of the piston, such as the lower crown area of the piston.

  Accordingly, it is known to promote cooling of the lower crown region via an electric oil pump system that forces pressure from the oil pump region to the lower crown region of the piston to force oil upward. Known mechanical or electric pumps can be effective at lowering the operating temperature of the piston, but are expensive. Typically, an electric pump requires about 2-3 kW of energy for a typical 6-cylinder high horsepower engine, and more energy for a larger engine. For this reason, the electric pump causes parasitic loss to the engine, which in turn causes deterioration in engine performance, engine efficiency, and fuel consumption.

  As will be apparent to those skilled in the art upon reading the disclosure and viewing the drawings, a piston constructed in accordance with the present invention overcomes at least the aforementioned disadvantages of known piston cooling systems.

SUMMARY OF THE INVENTION Pistons for internal combustion engines constructed in accordance with one aspect of the invention are economical in manufacture and exhibit a long service life. The piston includes a piston body having an upper combustion surface and an annular cooling cavity surrounding a lower crown region, an outer wall suspended from the upper combustion surface, and an annular ring belt region formed on the outer wall adjacent to the upper combustion surface Is done. The ring belt region has at least one ring groove formed therein. At least one oil passage extends from the at least one ring groove to the cooling cavity. The oil passage has a first portion suspended radially inward from at least one ring groove and a second portion rising radially inward from the first portion to the cooling cavity.

  According to a further aspect of the invention, the cooling cavity has a bottom surface and the oil passage extends through the bottom surface.

  According to a further aspect of the invention, the oil passage includes a tubular member extending upwardly from the bottom surface of the cooling cavity into the cooling cavity.

  According to another aspect of the invention, the counterbore is suspended from the bottom surface of the cooling cavity and the tubular member is secured to the counterbore.

  According to yet another aspect of the invention, the piston body includes an upper part fixed to the lower part, and the oil passage is completely formed in the lower part.

  According to yet another aspect of the invention, the piston body is configured as a single unitary piece of material.

  According to yet another aspect of the invention, the first portion is formed as an annular groove extending around the outer wall.

  According to yet another aspect of the invention, the second portion extends through the outer wall into the cooling cavity and is formed as a through hole that intersects the first portion.

  According to another aspect of the invention, a plug is disposed in the through hole adjacent to the outer wall to prevent oil flowing through the second portion from bypassing the cooling cavity.

  According to yet another aspect of the invention, a method for configuring a piston for an internal combustion engine is provided. The method includes forming a piston body having an upper combustion surface and an annular cooling cavity surrounding a lower crown region, with the annular ring belt region suspended from the upper combustion surface. Further, an oil ring groove is formed in the ring belt region. Still further, by forming a first portion of the oil passage suspended radially inward from the oil ring groove and a second portion rising radially inward from the first portion of the cooling cavity, the oil At least one oil passage extending from the ring groove to the cooling cavity is formed.

  According to another aspect of the invention, the method can further include forming an oil passage that extends through the bottom surface of the cooling cavity.

  According to another aspect of the invention, the method can further include forming a portion of the oil passage having a tubular member extending upwardly from the bottom surface of the cooling cavity.

  According to another aspect of the invention, the method can further include securing the tubular member to a counterbore extending to the bottom surface of the cooling cavity.

  According to another aspect of the invention, the method can further include forming a piston body by securing the upper part to the lower part, wherein the upper part and the lower part are in contact with the cooling cavity, and at least One oil passage is completely formed in the lower part.

  According to another aspect of the invention, the method can further include forming the piston body as a unitary piece of material.

  According to another aspect of the invention, the method includes forming the second portion as a through hole extending through the outer wall to the cooling cavity and placing a plug in the through hole adjacent to the outer wall. And can further be included.

According to another aspect of the invention, the method can further include forming the first portion as an annular groove extending around the outer peripheral edge of the outer wall.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects, features and advantages of the invention will be considered in conjunction with the following detailed description of the presently preferred embodiments and best mode, the appended claims and the accompanying drawings. More easily understood.

1 is a perspective view of a piston configured in accordance with one aspect of the invention. FIG. It is a fragmentary sectional view of the piston of FIG. 1B is a view similar to FIG. 1A of a piston configured in accordance with another aspect of the invention. FIG. 1B is a view similar to FIG. 1A of a piston configured in accordance with another aspect of the invention. FIG. FIG. 2 is a view similar to FIG. 1B of a piston configured in accordance with another aspect of the invention. 1B is an enlarged cross-sectional view of a schematic region surrounded by a circle 2 in FIG. 1A. FIG.

Detailed Description of Presently Preferred Embodiments Referring to the drawings in more detail, FIG. 1 illustrates a cylinder bore or chamber of an internal combustion engine, such as a new generation high performance gas or diesel engine, such as used in high performance vehicles and heavy trucks. 1 illustrates a piston 10 configured in accordance with an aspect of the invention for reciprocating motion in (not shown). Regardless of whether the piston 10 is a unitary single piece of material or a number of pieces of material secured together, any other known or known for making up the piston. And the body 12 extends along a central longitudinal axis 14 along which the piston 10 reciprocates within the cylinder bore. The body 12 has two parts including a top, also referred to as an upper crown 16, and a bottom, also referred to as a lower crown 18, as best illustrated in FIG. For example, by a friction welding process or the like, for example, friction welding joints or joints 17 and 19 are fixedly joined to each other. References herein to “vertical”, “top”, “bottom”, “upper”, and “lower” refer to the longitudinal longitudinal central piston axis 14 along which the piston 10 reciprocates along in use. With respect to the piston 10 oriented along the axis. This is for convenience in describing the relative structure position and is limited because the piston can be installed and actuated at an angle or purely other than vertically. is not. The lower crown 18 has a pair of pin bosses 20 that extend away from the upper crown 16 to provide laterally spaced pin bores 22. The pin bore 22 is aligned along a pin bore axis 24 that extends generally across the central longitudinal axis 14. The pin bosses 20 are joined to the skirt portions 26 that are diametrically spaced apart via the support column portions 28. Upper crown 16 has an upper combustion surface 30 that is shown as having combustion bowl 32 recessed to provide the desired gas flow to the cylinder bore. The body 12 has a cylindrical or substantially cylindrical outer wall 34 that is suspended from the upper combustion surface 30, the outer wall 34 being directly adjacent to the upper combustion surface 30 and a vertically extending upper land 36. A ring belt region 38 formed in the outer wall 34 adjacent to the upper combustion surface 30 and suspended vertically from the upper combustion surface 30 and the upper land 36. An annular toroid-shaped cooling cavity 40 is formed radially inward from the ring belt region 38 and aligned with the ring belt region 38 in the radial direction. The cooling cavity 40 extends around the lower crown region 42 disposed immediately below the upper combustion surface 30 and surrounds the lower crown region 42 in the circumferential direction. The ring belt region 38 is formed with at least one ring groove shown as a plurality of ring grooves including a compression ring groove 44, a wiper ring groove 46, and a lowermost oil ring groove 48. At least one oil passage 50 extends continuously from the oil ring groove 48 to the cooling cavity 40.

As best shown in FIG. 1A, the oil passage 50 has a first portion 52 suspended radially extending from the oil ring groove 48 (extending downward) and a cooling cavity directly from the first portion 52. 40 is formed as a continuous uninterrupted passageway including a second portion 54 that rises radially inward (extends upward). Therefore, the oil passage 50 does not follow a continuous linear path, and therefore, the downward and upward extending path formed by the oil passage 50 is generated in response to the reciprocating motion of the piston 10 upward and downward. The oil rubbed off from the cylinder wall by the hydraulic pressure wave flows into the cooling cavity 40. Therefore, it is ensured that sufficient oil is supplied to the cooling cavity 40 and the lower crown region 42 through the oil passage 50, and the piston does not need to be supplied from a mechanically or electrically started oil pump. Ten desired operating temperatures are maintained at a temperature consistent with the desired piston application. However, oil rubbed in this way can also be used to supplement the less flow supplied by existing pumping mechanisms. Total flow power absorption is less than a single mechanical or electrical coolant supply, thereby maximizing engine running efficiency and performance.

  The upper crown 16 is shown by way of example, but not limited to, having an annular inner rib 56 that suspends from the lower surface of the combustion bowl 32 to an inner upper joint surface, also referred to as an inner free end. The upper crown 16 also has an annular outer rib 58 formed as part of the wall surface 34, which suspends to the outer upper interface and is also referred to as the outer free end. The compression ring groove 44 is shown as being formed in the upper crown 16 and the other grooves 46 and 48 are shown as being formed in the lower crown 18.

  Although not limited, the lower crown 18 is configured separately from the upper crown 16 as an example in a forging process or the like. The lower crown 18 is joined to the upper crown 16 via at least one upstanding annular outer lower joining surface, also referred to as an upstanding annular outer rib 60, and to the upper crown 16 via an upstanding annular inner rib 62. Are also shown as being joined. When the upper and lower crowns 16, 18 are welded together, such as, but not limited to, friction welding, across the respective outer ribs 58, 60 and inner ribs 56, 62, the substantially closed outer oil holes 40. Are formed as ribs 56, 58, 60, and 62 of the upper and lower crowns 16, 18, an upper wall portion 64 of the combustion bowl 32, also referred to as a seal, and as part of the lower crown 18 In contact with the lowermost floor surface 66 of the cooling cavity 40 shown as. Further, when the upper and lower crowns 16, 18 are joined together, an open inner cavity 68 is formed above the pin bore 22 below the central portion of the lower crown region 42 located radially inward from the cooling cavity 40. The It should be appreciated that a piston 10 constructed in accordance with the invention may have upper and lower crown portions formed in other ways, for example, having differently structured oil holes. Further, the lower crown 18 includes, by way of example, a lower portion of the ring belt region 38 by including a wiper ring groove 46 and a lowermost oil ring groove 48 for receiving the oil ring 70 (FIG. 2). Are shown as forming. However, it should be appreciated that these ring grooves 46 and 48 can be formed in the upper crown 18 if desired. Still further, as shown in FIG. 1B, a structure similar to that described above is represented by adding the same reference number as the one used above to the 100th place. A piston 110 constructed in accordance with another aspect of the invention can be formed as a monolithic piece of material, thereby forming a piston body 112 that is a single piece of material. Of course, the piston body 112 includes all the same ring grooves 144, 146, 148 described above and an oil passage 150 including the cooling cavity 140 described above and the first and second portions 152, 154. Therefore, no further discussion on the integrally structured piston body 112 is necessary.

The oil passage 50 includes intersecting first and second portions 52, 54, shown in FIG. 1A as being formed entirely within the lower crown 18, and thus the first and second portions 52, 54. 54 can be formed before the upper and lower crowns 16, 18 are secured together. The first portion 52 is machined into the bottom surface of the oil ring groove 48 as an annular groove, channel or recess, so that the first portion 52 is in direct fluid communication with the oil ring groove 48 and below the oil ring groove 48. It extends in the axial direction. Therefore, the first portion 52 extends around the entire outer periphery of the ring belt region 38, and the oil scraped off by the oil ring 70, such as during an upward stroke of the piston 10, is retained in the lower crown 18. Flowed downwardly to a first portion 52 extending around the entire outer periphery. From the first portion 52, oil then flows upwardly through the second portion 54 of the oil passage 50 and into the cooling cavity 40, such as during a downward stroke of the piston 10. The second portion 54 is formed as a hole extending upward and radially inward through the outer surface of the cylindrical wall 34 to the cooling cavity 40, and the second portion 54 is formed at the intersection 71. Crosses the first portion 52. Thus, the first and second portions 52, 54 are in fluid communication with each other. The second portion 54 is formed as a through-hole extending through the outer surface of the outer wall 34 and through the floor surface 66 of the cooling cavity 40, so that the plug 72 extends directly through the outer surface of the cylindrical wall 34. Placed in place of the hole with a press fit. Therefore, the plug 72 is between the outer surface of the outer wall 34 and the intersection 71 of the first and second portions 52 and 54. Therefore, the oil flowing in the oil passage 50 is prevented from exiting from the lower part of the through hole outward from the cylindrical wall 34, so that once the oil is collected in the first part 52, the oil is second Always flows upward into the cooling cavity 40 through the portion 54. Once in the cooling cavity 40, the oil is vibrated into a cocktail shaker, thereby cooling all surfaces in contact with the cooling cavity 40. As the oil is oscillated within the cooling cavity 40, the oil then flows outwardly from the cooling cavity 40 through an oil hole or port 74 to the inner cavity 68. Thus, the oil can further cool the lower crown region 42 and lubricate the innermost region of the piston 10, including the pin boss 20, pin bore 22, and the small end of the connecting rod.

  In order to facilitate the flow of oil from the cooling cavity 40 to the inner cooling cavity 68 and to prevent the oil from flowing back from the cooling cavity 40 through the oil passage 50, it extends outwardly from the second portion 54. As is present, a tubular member 76 is secured within the second portion 54. By way of example and not limitation, the tubular member 76 is shown as being disposed in an enlarged counterbore 78 extending from the floor surface 66 to the second portion 54, thereby reducing the inner diameter of the tubular member 76 to a second. Can be the same or substantially the same as the inner diameter of the portion 54, thus maximizing oil flow through the second portion 54 into the chamber 40. A geometric structure can be designed for the oil inlet 50 that will maximize scraping and oil collection into the first portion 52. In the embodiment of FIG. 1A, since the tubular member 76 has an outer diameter that is larger than the diameter of the second portion 54, it is not possible to extend through the second portion 54, so And the lower crowns 16, 18 are secured within the counterbore 78 prior to securing them together. In the embodiment of FIG. 1B, the tubular member 176 can be pushed into the second portion 154 formed by the through-hole and the cooling cavity 140 so that the tubular member 176 fits or fits within the second portion 154. Provided with a line-to-line fit. The tubular member 76 is about 1.0-5.0 mm, preferably about 2.0-2.0, in an inclined relationship with respect to the central longitudinal axis 14 upward from the bottom surface 66 and outward from the second portion 54. Extend a predetermined distance X, such as between 4.0 mm. Therefore, since the tubular member 76 extends over the stored oil, any oil reservoir along the floor surface 66 of the cooling cavity 40 cannot flow back through the oil passage 50. Another means of achieving a similar action is in the pistons 10 ', 110' as shown in FIGS. 1C and 1D, respectively, such that the protrusions 76 ', 176' are a piece of material that is integral with the floor 66. Local protrusions 76 ′, 176 ′ are forged on the floor 66 and drilled through the protrusions 76 ′, 176 ′ so that they are integral with the respective parts 18, 112 of the pistons 10 ′, 110 ′. The tubular member 76 is provided as a piece of material. Thus, the oil flow path is unidirectional and flows through the second portion 54 into the cooling chamber 54 and not in the reverse direction, so that the oil flows out of the cooling cavity 40 through the oil port 74. It is ensured that the desired amount of cooling is provided in the cooling cavity 40 before.

According to another aspect of the invention, a method of configuring a piston 10 for an internal combustion engine is provided. The method includes forming a piston body 12 having an upper combustion surface 30 and an annular cooling cavity 40 surrounding a lower crown region 42, with an annular ring belt region 38 suspended from the upper combustion surface 30. Further, an annular oil ring groove 48 is formed in the ring belt region 38. Furthermore, a first portion 52 of the oil passage 50 that is suspended radially inward from the oil ring groove 48 and a second portion 54 that rises radially inward from the first portion 52 to the cooling cavity 40 are provided. By forming, at least one oil passage 50 extending from the oil ring groove 48 to the cooling cavity 40 is formed. The method further includes forming the first portion 52 as an annular channel that extends around the entire periphery of the ring belt region 38.

  The method may further include forming an oil passage 50 through the bottom surface 66 of the cooling cavity 40 according to another aspect of the invention. Still further, according to yet another aspect of the invention, the method forms a portion of the oil passage 50 having a tubular member 76 that extends a predetermined distance above the bottom surface 66 of the cooling cavity 40 into the cooling cavity 40. Can further include. Still further, according to yet another aspect of the invention, the method can include securing the tubular member 76 to a counterbore 78 that extends to the bottom surface 66 of the cooling cavity 40.

  The method may further include forming the piston body 12 by securing the upper part 16 to the lower part 18, where the upper and lower parts 16, 18 are in contact with the cooling cavity 40 and the lower part 18. The oil passage 50 is formed at

  According to another aspect of the invention, the method further includes forming the first portion 52 as an annular groove that extends continuously around the periphery of the piston head.

  The method further includes forming the second portion 54 as a hole, such as in a drilling operation, according to another aspect of the invention. Still further, the method forms the second portion 54 as a through hole that opens at the opposite end, and then places one of the ends adjacent to the outer surface of the cylindrical wall 34 below the first portion 52. And plugging with plug 72.

  The method can further include forming the piston body 112 as a unitary piece of material.

  Thus, an engine that includes the pistons 10 and 110 described and exemplified above significantly reduces the need for energy consumption by the electric oil pump, if included, and is effective at operating pistons below operating temperatures consistent with specific piston applications. It should be recognized that the cooling is automatic. This is due to a reduction in the burden on the oil pump for cooling the pistons 10 and 110 due to the presence of the oil passage 50. Furthermore, in some engines, the need for an oil pump that consumes power can be eliminated completely, and the oil passage 50 is only responsible for maintaining the pistons 10, 110 at operating temperatures below 240-270 ° C. It should be recognized that it can.

  Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that the invention may be practiced otherwise than as specifically described within the scope of the appended claims and any further claims ultimately permitted.

Claims (1)

A piston for an internal combustion engine,
A piston body having an upper combustion surface and an annular cooling cavity surrounding a lower crown region, an outer wall suspended from the upper combustion surface, and an annular ring belt region formed on the outer wall adjacent to the upper combustion surface The ring belt region has at least one ring groove formed therein, and
And at least one oil passage extending continuously from the at least one ring groove to the cooling cavity, the at least one oil passage suspended radially inward from the at least one ring groove. And a second part that rises radially inward from the first part directly into the cooling cavity;
Oil in the first portion flows upward into the cooling cavity through the second portion, and then the oil flows from the cooling cavity through an oil port into an inner cavity ;
The oil port, Ru holes der provided inside the ribs between the cooling cavity and the inner cavity, a piston.